In an image-forming apparatus such as a printer, electronic photocopier, and facsimile apparatus, as the mechanism where semiconductivity is required, a conductive member such as a conductive roll, conductive blade, and conductive belt has been used.
Such a conductive member, depending on their application, are being required to provide various performances such as electroconductivity (an electrical resistance value and variation in the same, environmental dependency, and voltage dependency) within a desired range, non-contaminating ability, low hardness, and dimensional stability.
As the rubber constituting part of such a conductive member, a polyether rubber and the like which have semiconductivity in the rubber itself have been used. However, in recent years, in the image-forming apparatus, higher speed has been demanded. For the conductive member, particularly the conductive roll, further lower electrical resistance has been desired.
Further, there has been conventionally the following problem: under application of voltage to a conductive member in which a polyether rubber and the like are used, upon continuous use, the conductive member deteriorates due to electric current so that the electrical resistance value of the conductive member increases and quality of an image is impaired accordingly when the conductive member is used for the application of an image-forming apparatus. To solve this problem, for example, Patent Document 1 discloses a polyether rubber obtained by kneading using an extruder-kneader a polyether rubber containing epihalohydrin monomer unit in 0.1 mol % or more and a nitrogen atom-containing aromatic heterocyclic compound in the presence of 2.4 to 6.4 parts by weight of acid acceptors such as magnesium oxide and calcium carbonate with respect to 100 parts by weight of the polyether rubber.
However, when magnesium oxide, calcium carbonate, and the like are used as acid acceptors in such a relatively high addition ratio, the adhesion of the obtained polyether rubber to the rolls used in kneading is increased when the polyether rubber is mixed with a cross-linking agent and kneaded for cross-linking, thus posing the problem of poor processability, and the polyether rubber also has the problem in that the suppressing effect of the obtained cross-linked rubber on an increase in the electrical resistance value during continuous use is not sufficient.